I would suggest taking US 2 across the northern US. We took it all the way to Michigan, then dropped down and came around the Great lakes to Niagra Falls then into Bangor.
Proceeded south along US 1 into New and York and south to DC. On that trip we came back west on US 36-38. Another trip was to angle down to Corpus Christi and then around the Gulf of Mexico to Key Wets, up the east coast to Virginia and then snaked down the Smokey Mountain Trail.
Hate to tell you but each of these trips was over 2 months.
I would make a list of your planned route, send a tourism request to each state and province to give you a better idea of sites you want to visit.